1. Field of the Invention
The present invention relates generally to septic systems for the treatment of sewage and wastewater and, more particularly, relates to a modular, self-contained subsurface sewage disposal/wastewater treatment system that provides improved biomat formation, improved distribution and treatment of effluent within a leach field of the system, and that is detectable within the leach field for post installation location and inspection.
2. Related Art
Septic systems, also known as subsurface sewage disposal/wastewater treatment systems, are extensively used to treat sewage and wastewater from individual residences, businesses, schools, churches, military bases, or like residential and/or commercial structures, in areas not served by sewers. In the treatment of sewage and wastewater by septic systems, solid and liquid waste from these structures, is collected in a septic tank. Because of the different densities of solid and liquid waste, the solid and liquid components of the sewage separate. The solid material is at least partially decomposed within the tank by the action of aerobic, facultative and anaerobic bacteria, resulting in a liquid effluent. The liquid effluent, which may contain suspended solids, is then conveyed out of the tank and distributed through an area of subterranean soil, which is typically referred to as a drain or leach field. The liquid effluent is passed to a series of stone or sand trenches or chambers within the leach field. The effluent percolates through the chambers and soil for treatment to reduce contaminants before being mixed with the underground water table.
Leach fields are typically divided into a number of portions (e.g., the aforementioned trenches and chambers) as dictated by the sewage treatment requirements of the structure serviced. Preferably, the effluent is distributed to the portions over a wide area to avoid, or at least substantially minimize, over-saturation of any one portion of the leach field. A plurality of underground tubes or pipes connects the septic tank to each of the portions of the leach field. Due in part to excavation needed to reach subsurface components as well as associated material and labor costs, the installation, repair and re-installation of the components of the septic system can be relatively expensive.
As can be appreciated, it is desirable to minimize installation costs and to extend the useful life of a septic system to minimize maintenance and repair costs. It is also desirable to maximize the density of treatment surfaces within each linear unit of leach field length to ultimately reduce or at least minimize the leach field area. It is further desirable to maximize the leach field's ability to evenly distribute wastewater across the full expanse of wastewater treatment surface provided by the leach field components. It is additionally advantageous to provide subsurface components that can be detected above the surface to permit post installation location for inspection and/or future maintenance.
The inventors have found that the conventional use of stone as a treatment medium can result in premature failure of a septic system leach field as the stone may be “dirty,” for example, contain contaminants or fine particles that may obstruct proper flow within the system and reduce percolation into the surrounding soil. As such, the exclusion of stone as a treatment medium is a desirable improvement over the existing art.